In order to profile a program, you must first to tell the compiler
to generate the necessary profiling information. You do this using the compiler switch -pg, which you must add to other compilation switches. You need
to specify this
switch during compilation and link stages, and you can
specified it only once when using gnatmake:
$ gnatmake -f -pg -P my_project
Note that only the objects that were compiled with the -pg switch will
be profiled; if you need to profile your whole project, use the -f
gnatmake switch to force full recompilation.
Note that on Windows, gprof does not support PIE. You should add
the -no-pie switch to the linker flags to disable PIE.